Madison Keys and Sloane Stephens will meet in the first all-American women’s final at the US Open in a decade and a half after winning their semi-finals on Thursday night at Arthur Ashe Stadium.

There is still another match to be played in this most improbable tournament but one thing is certain: the United States is guaranteed a grand slam champion not named Williams for the first time since Andy Roddick in 2003 – and the first on the woman’s side since Jennifer Capriati in 2002.